// Copyright 2001-2006, FreeHEP.
package org.freehep.graphicsio.emf;

import java.io.IOException;

import org.freehep.util.io.Tag;
import org.freehep.util.io.TaggedInputStream;
import org.freehep.util.io.TaggedOutputStream;

/**
 * EMF specific tag, from which all other EMF Tags inherit.
 * 
 * @author Mark Donszelmann
 * @version $Id: EMFTag.java,v 1.5 2009-08-17 21:44:45 murkle Exp $
 */
public abstract class EMFTag extends Tag {

    protected int flags = 0;

    /**
     * Constructs a EMFTag.
     * 
     * @param id id of the element
     * @param version emf version in which this element was first supported
     */
    protected EMFTag(int id, int version) {
        super(id, version);
    }

    public Tag read(int tagID, TaggedInputStream input, int len)
            throws IOException {

        EMFInputStream emf = (EMFInputStream)input;
        EMFTagHeader tagHeader = (EMFTagHeader)emf.getTagHeader();
        flags = tagHeader.getFlags();
        return read(tagID, emf, len);
    }

    public abstract EMFTag read(int tagID, EMFInputStream emf, int len)
            throws IOException;

    public void write(int tagID, TaggedOutputStream output) throws IOException {
        write(tagID, (EMFOutputStream) output);
    }

    /**
     * Writes the extra tag information to the outputstream in binary format.
     * This implementation writes nothing, but concrete tags may override this
     * method. This method is called just after the TagHeader is written.
     * 
     * @param tagID id of the tag
     * @param emf Binary EMF output stream
     */
    public void write(int tagID, EMFOutputStream emf) throws IOException {
        // empty
    }
    
    public int getFlags() {
        return flags;
    }

    /**
     * @return a description of the tagName and tagID
     */
    public String toString() {
        int id = getTag();
        return "EMFTag " + getName() + " (" + id + ") (0x"+Integer.toHexString(id)+")";
    }
}
